Tungsten oxide nanomaterials have been widely studied due to their excellent gas sensitivity, photocatalysis, electrochromic and other properties. Tungsten trioxide (WO3) with nanostructures is expected to be a candidate material for gas sensors for detecting various gases (NH3, H2S, NO2, CH3OH, etc.). Tungsten oxide nanomaterials with specific size and morphology are synthesized by thermal oxidation method, hydrothermal method, electrochemical anodic oxidation method and other methods. Hydrothermal synthesis specifically shows much more advantages of more effective, low cost, easier to operate and environmentally friendly.

As a typical exhaust gas from industry and automobiles, nitrogen dioxide (NO2) not only causes environmental problems, but also affects the human health. Tungsten trioxide (WO3) is an n-type semiconductor oxide, which has proven to be particularly suitable for detecting NO2 gas.

Tungsten trioxide (WO3) is a non-toxic n-type semiconductor with an indirect and general wide band gap in the range of 2.4-3.6 eV. Therefore, it is an excellent candidate for applications in various fields of industry, medicine, science and military engineering. This effect is due to the unique properties of tungsten oxide nanostructures and their composite materials, such as excellent thermal corrosion resistance and good ductility, high density, strength and elastic modulus, amazing antibacterial activity, and efficient heat and activity Oxygen (ROS) production through light interaction.

The main source for water and soil pollutions is hazardous colorants in waste water discharged from textile industries. Rhodamine B (RhB) is the most used dye in the textile industries hence it is widely considered as a typical water pollutant. Among the several methods available today, the removal of Rhodamine B dye from the textile waste water via photocatalytic degradation has received much attention from researchers because it can convert the Rhodamine B dye into water, carbon di-oxide and mineral acids without creating secondary pollutants.